Ernest Willis, a New Hampshire man accused of raping a 15-year-old girl from his church in 1997, pleaded guilty to statutory rape just days before his trial was set to begin. The victim, Tina Anderson, who became pregnant with Willis' child, said she was forced to confess her "sin" -- the pregnancy -- in front of their congregation.

Willis, 51, of Gilford, N.H., admitted on Wednesday that he raped and impregnated Anderson, now 28, but maintained that the sex was consensual.

Willis is also charged with three counts of forcible rape and an additional count of felonious sexual assault, but he could face up to seven years in prison for the statutory rape charge alone. The trial date is scheduled for May 23.

In an April interview with "20/20," Anderson said that after being sexually assaulted twice by Willis, she was forced to stand before her Baptist congregation and confess her "sin" -- that she had become pregnant. She said she wasn't allowed to tell the group that the pregnancy was the result of being raped by Willis, a man twice her age.

Anderson and Willis were members of Trinity Baptist Church, an Independent Fundamental Baptist Church (IFB) in Concord, N.H.

"I still struggle, because I've been made to feel guilty for so long," Anderson said.

At the age of 14, Anderson was hired as a babysitter for the Willis family. She said the first assault occurred in the backseat of a car during a driving lesson. Anderson said Willis pulled her into the back of the car and raped her.

According to Anderson, the second assault occurred at her home when Willis showed up unannounced.

"He locked the door behind him and pushed me over to the couch. I had a dress on and he pulled it off. I pushed my hands against his shoulders and said 'No,' but he didn't stop," Anderson said.

After Anderson summoned the courage to tell her mother, Christine Leaf, that she was pregnant, Leaf contacted their local pastor, Chuck Phelps. Anderson said it was Phelps who insisted on her making a public apology.

At the same meeting, the church congregation also heard a confession from Willis that he had been unfaithful to his wife. Former church members told "20/20" that the confessions were presented as separate issues and there was no suggestion that Willis was the father of Anderson's baby.

Phelps, now a pastor at another IFB church, told "20/20" that Anderson voluntarily stood before the congregation in 1997, that he reported Willis to the Concord Police and complied with all legal requirements of him at the time. He is on the prosecution's list of witnesses and expected to testify next week.

After she announced she was pregnant, Phelps and Anderson's mother arranged to send her thousands of miles away to Colorado to live with another IFB family. According to Anderson, the local pastor in Colorado, Matt Olson, told her to write a letter to Willis' wife apologizing for her part in what happened.

Olson declined to speak to "20/20," saying through his lawyer that his conversations with Anderson remained privileged.

In March 1998, Anderson gave birth to a baby girl. Adoption records show that Willis admitted he was the father.

Thirteen years after the alleged crime, Matt Barnhart, a former member of Anderson's church, who was present when she confessed to being pregnant in 1997, wrote a post referencing her story on a Facebook page called, "Independent Fundamental Baptist (IFB) Cult Survivors (And their Supporters)."